SIZE-EXCLUSION CHROMATOGRAPHY IN AN ANALYTICAL PERSPECTIVE

Modern media for size-exclusion chromatography combine maximum selecti vity with high plate count to resolve solutes differing in molecular m ass by as little as 20%. Separations of solutes differing in molecular mass by only 10% will be very hard to accomplish even for rod-shaped molecules. The reduced column lengths and porosity of small-particle-s ized media unfortunately reduces the inherent resolving power to the s ame order as traditional columns but with a substantial reduction in a nalysis time. The use of well-calibrated columns for obtaining estimat es of molecular mass yields a precision close to that of absolute meth ods. The simplicity and accuracy of the integral calibration method us ing a sample of broad molecular mass distribution makes this procedure very suitable for manual calibration of size-exclusion columns.